MASINT is scientific and technical intelligence information obtained by quantitative and qualitative analysis of data derived from specific technical sensors for the purpose of identifying any distinctive features associated with the source emitter or sender. This information is then used to facilitate the subsequent identification or measurement of the same type of equipment. The term measurement refers primarily to the data collected for the purpose of obtaining finite metric parameters. The term signature refers primarily to data indicating the distinctive features of phenomena, equipment, or objects as they are sensed by the collection instrument. The signature is used to recognize the phenomenon, equipment, or object when its distinctive features are detected.
Examples of MASINT disciplines include radar intelligence (RADINT), infrared intelligence (IRINT), and nuclear intelligence (NUCINT). Because it works in different parts of the electromagnetic spectrum, MASINT detects information patterns not previously exploited by sensors. MASINT sensors collect information generally considered by the targeted nation to be peripheral in nature. As a result, these signatures are often not protected by any countermeasures.